A is the larger of two commonly occurring
Musical Interval s that span three
Diatonic Scale degrees. The prefix 'major' identifies it as being the larger of the two (by one
Semitone ); its smaller counterpart being, a
Minor Third . The major third is abbreviated as '''M3''' and its
Inversion is the
Minor Sixth .
The
Major Scale is so named because of the presence of this interval between its
Tonic and
Mediant (1st and 3rd)
Scale Degrees .
Major Chord s too, take their name from the presence of this interval built on the chord's
Root (provided that the interval of a
Perfect Fifth from the root is also present or implied).
A Major third in s, 13.686 cents larger. The older concept of a
Ditone (two major seconds=major third) is the pythagorean ratio 81:64 (1.2656= 1.125
2, two major seconds).
The major third is one of the most consonant intervals after the
Unison ,
Octave ,
Perfect Fifth , and
Perfect Fourth . In the
Common Practice Period , thirds were considered interesting and dynamic consonances along with their inverses the sixths, but in
Medieval Times they were considered dissonances unusable in a stable final sonority.
See also:
